<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
    <title>Title</title>
</head>
<body>

<canvas id="canvas"></canvas>

<script>
    (function draw() {
        var ctx = document.getElementById('canvas').getContext('2d');
        for (var i = 0; i < 6; i++) {
            for (var j = 0; j < 6; j++) {
                ctx.fillStyle = 'rgb(' + Math.floor(255 - 42.5 * i) + ',' +
                    Math.floor(255 - 42.5 * j) + ',0)';
                ctx.fillRect(j * 25, i * 25, 25, 25);
            }
        }
    })();
</script>
</body>
</html>